1. Field of the Invention
The present invention relates to a water-supply valve of a washing machine, and more particularly to a water-supply valve of a washing machine in which the consumption of electric power can be minimized in opening and closing the valve to supply water into and block off the water supply from a washing tub of the washing machine.
2. Description of the Prior Art
FIG. 5 is a side sectional view for showing a conventional water-supply valve of a washing machine, which is opened or closed by operation of solenoids to cause water to be supplied into or blocked off from a washing tub of the washing machine therethrough.
Referring to FIG. 5, a water-introducing tube 11 for inducing water is connected to a valve body 10 of the water-supply valve assembly, and a water-supply tube 12 for supplying water into the washing tub is vertically connected to valve body 10 near water-introducing tube 11. A reservoir 13 for interconnecting water-introducing tube 11 and a water-supply tube 12 is defined directly above water-supply tube 12.
A diaphragm 20 is disposed on the bottom surface of reservoir 13 and is in close contact with water-introducing tube 11 and a water-supply tube 12 to separate reservoir 13 therefrom. Diaphragm 20 has a water-inflow port 21 formed at an outer portion thereof to interconnect water-introducing tube 11 and reservoir 13 in order for water to flow into reservoir 13 therethrough, and a water-exhaust port 22 at the center thereof to interconnect reservoir 13 and water-supply tube 12 in order for water having been retained in reservoir 13 to be supplied into the washing tub therethrough.
An actuator chamber 31 interconnected to reservoir 13 is defined above reservoir 13 by a cylindrical wall 10a within the actuator housing of the water supply valve assembly. A solenoid 40 for generating magnetic force when electric power is supplied is disposed in cylindrical wall 10a.
An actuator rod 60 for opening/closing exhaust port is disposed in actuator chamber 31. Actuator rod 60 is elastically supported on the bottom of actuator chamber 31 by a spring 50.
In the above described conventional water-supply valve assembly, when water is not supplied into the washing tub, water-exhaust port 22 is closed so that water is not supplied but retained in reservoir 13, and accordingly the pressure in reservoir 13 is maintained to be the same as that in water-introducing tube 11.
In order to supply water into the washing tub, a voltage is applied to solenoid 40 so as to generate a magnetic force by solenoid 40. Then, actuator rod 60 is moved upward in actuator chamber 31 while compressing spring 50, and accordingly the water having been retained in reservoir 13 is supplied into the washing tub through water-exhaust port 22. Therefore, the pressure in reservoir 13 becomes lower than that in water-introducing tube 11, so diaphragm 13 is elevated by the pressure of the water flowing into reservoir 13 from water-introducing tube 11. Then, water-introducing tube 11 is directly interconnected to water-supply tube 12, so that water flows directly from water-introducing tube 11 into water-supply tube 12 without passing through water-inflow port and water-exhaust port.
When the voltage having been applied to solenoid 40 is interrupted, actuator rod 60 is restored to its initial position by spring 50, so water-exhaust port 22 is closed again.
In the above described conventional water-supply assembly, electric power supply to solenoid 40 must be continued while water is supplied into the washing tub, so the electric power consumption is too large. Further, fine wires of solenoid 40 can be broken or solenoid 40 can catch on fire due to heat generated by the continuous application of voltage to solenoid 40 during water supply.